In a semiconductor manufacturing process, a plasma processing apparatus which performs plasma processing for the purpose of, for example, deposition, or etching of a thin film, has been widely used. To obtain a high-performance and multi-functional semiconductor, it is desirable to perform a uniform plasma processing on a surface of an object to be processed.
In the recent plasma processing, a plasma processing apparatus which generates plasma of a processing gas using a high frequency power having a relatively high frequency has been used. The plasma processing apparatus supplies a high frequency power of which the frequency is, for example, 100 MHz as a plasma generating power. Further, the plasma processing apparatus supplies a high frequency power having a frequency lower than that of the plasma generating power as a biasing power for implanting ions in the plasma toward the object side to be processed.
However, in the plasma processing apparatus, the plasma density at a central portion of the object to be processed is higher than that at a peripheral portion of the object to be processed. As a result, it has been known to mount a member that makes the plasma density uniform in a mounting unit of the object to be processed. For example, Japanese Patent Application Laid-Open No. 2008-243973 discloses making the plasma density uniform by forming a dielectric layer in a region corresponding to the central portion of the object to be processed inside the mounting unit thereby weakening the electric field supplied from the central portion of the object to be processed to the plasma by the dielectric layer.